


West Risen Sun

by snickerdoodlles



Category: Haikyuu!!
Genre: Alternate Universe - Merpeople, Alternate Universe - Royalty, Arranged Marriage AU, M/M, Osamu POV, Vaguely Historical, kita has one emotion and that emotion is stone, mer hinata & bokuto, royalty miya twins and sakusa
Language: English
Status: In-Progress
Published: 2020-02-14
Updated: 2020-02-14
Packaged: 2021-02-19 14:27:15
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,565
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22712248
Author URL: https://archiveofourown.org/users/snickerdoodlles/pseuds/snickerdoodlles
Summary: Out in a black ocean with waves rising like mountains, a mermaid of gold saves a drowning man.This is not that story.This is what comes after.
Relationships: Hinata Shouyou/Miya Atsumu, Miya Atsumu & Miya Osamu, Miya Osamu/Sakusa Kiyoomi
Comments: 14
Kudos: 109





	West Risen Sun

**Author's Note:**

> i saw [@atsuhinas](https://twitter.com/atsuhinas?s=20)'s adorable [mermaid](https://twitter.com/atsuhinas/status/1226964555240235011?s=20) [arts](https://twitter.com/atsuhinas/status/1227323906220068864?s=20) monday and realized i didn't have a mermaid au for atsuhina yet (a tragedy only my most unfortunate friends know). i jotted down some notes tuesday night and got writing as soon as i woke up wednesday in hopes of finishing it by valentines day despite being the middle of a work week
> 
> well
> 
> its valentines. im still writing
> 
> welcome to the beginning

☼

Osamu’s pulled from his daze by a harsh snap right beside his ear.

“What the _hell_ —” he begins, twisting in his seat to glare up at Kita.

His secretary’s expression, as always, is as placid as a mountain lake. “Good, you’re awake.” He slaps down a stack of papers and thrusts a pen in front of Osamu’s nose. “Sign.”

Osamu glares at the pen, cross-eyed, unable to back away thanks to Kita half-standing behind his chair to trap him in his desk. “I’m busy.”

“You’re not, you’re worrying about your brother.”

Osamu flinches, anger scraping up his throat. It’s been a week since Atsumu’s ship was reported missing. Atsumu’s body hasn’t been recovered, but that only offers untold mysteries when it involves the sea—he could be alive, stranded on a beach or drifting in the waves, or he could be leagues below the currents, already bones in some fish’s stomach. The endless possibilities have been plaguing Osamu night and day, pulling deep shadows from his eyes into purple bruises and sallow cheeks. Osamu doesn’t give a fucking _shit_ about paperwork right now.

“Sign them yourself.”

Kita doesn’t drop his hand. He looks as though he could stay standing there for the rest of eternity. “These are treaties needed to be signed for your upcoming nuptials with the Itachiyama prince. I won’t forge these.”

“They can wait.”

“They could,” Kita agrees amicably. “But they shouldn’t, and you need something to do. Sign.”

Osamu swallows his next furious retort, tucking it into the storm raging beneath his blank facade. He reluctantly takes the pen and stares down at the papers before him, words spinning into blurs. He can feel every lurch of the world, like a ship beneath his feet, and his fingers tighten to a white knuckled fist. Kita waits, patient as stone.

Osamu blinks until his vision clears. The words on the paper still don’t register, and for all he knows these are reams of senseless characters whose only purpose is to take his mind from darker things. “I—”

The words never manifest. The silence stretches, and Kita doesn’t do anything for a long moment. In that time, Osamu’s managed to move his pen to the paper, but nothing more.

Then a gentle, impassive hand rests on his shoulder. “The world keeps turning,” Kita says quietly. His voice is as bland as rice, but it soothes the knot twisted in Osamu’s chest. “Tomorrow will come, as sure as the next minute, and it’ll bring either news or peace. But first, it has to come,” Kita says, and then he moves away.

Osamu’s hand trembles, but he begins to sign. He doesn’t know how long it takes him, or even how many pages he gets through. Kita doesn’t appear to care how long he waits, only moving to pull away the sheets as Osamu finishes and gently waving them to help the ink dry.

Osamu makes it halfway through the stack before a servant bursts into the room, startling Osamu into splashing ink across an entire page of Kita’s beautiful calligraphy. He stares blankly at the boy wheezing in his doorway, trying to comprehend why the bus boy from the kitchens needs his attentions now of all times.

“Your Majesty!” the boy huffs between gasping breaths. “I— the cook— we were going out for a— we were going down to the—”

Osamu’s voice cracks through the room like a whip. “Get to the point.”

The boy squeaks, his knees audibly knocking together. “The Prince! He’s—”

“ _Home~_ ” interrupts a new voice.

The bus boy lets out a high pitched _meep_ and scuttles out of the way just in time for Atsumu to swing into the doorway and lean lazily against the frame. “Hiya ‘Samu!”

Osamu sees red—all the worry and grief boils through him in a flash and then he’s bolting from behind his desk and across the room faster than anyone can register, hands outstretched to wrap around that stupid neck. “You fucking bastard!” he screams, hands fisting Atsumu’s collar. He yanks him close, foreheads not quite hitting, and resists the urge to shake. “You absolute _fucker_ , thinking ya can just fucking strut in here—”

Atsumu laughs and pokes the deep wrinkle between Osamu’s brow, the same way he liked to tease when they were kids. But his laugh is all wrong, breathless and watery, and then Osamu notices the way Atsumu’s eyelashes flutter from exhaustion and his dazed eyes can’t seem to focus properly. The shirt clenched between his fingers is sun-worn and underneath, his neck and cheeks are sunburnt to the point of blistering. Atsumu’s chapped lips are cracked dry and little beads of blood blot them as Atsumu’s grin stretches crookedly. Osamu’s hands fall away, but he immediately has to catch Atsumu’s shoulders as his twin sways dangerously.

“Hey, hey, guess what, ‘Samu.” Atsumu giggles, eyes clouded. “I got saved by an _angel_.”

Then, his eyes roll to the back of his head and he drops like a stone.

☼

Osamu and Atsumu are born princes to the little seaside kingdom of Inarizaki. Their castle used to be a small seaside fortress, and it sits high on the grey shale cliffs that spill from Inarizaki’s famous misty mountain forests. Their father and uncle had dominated the forests, so the twins had taken to exploring the shoreside instead, trading the heady scent of mulch and pine for brine and fish, exchanging trees stretching into the white-grey heavens for a hammered silver horizon and its boundless opportunities. They know all the hidden trails spilling down the cliffs like little brooks, know which rock is ready to crumble and which rock is secure as stone as well as they know each other, know which cliffs promise secrets and which ones promise death. These cliffs and narrow shores are their own little corner of the world where they can escape to and just be brothers, and Osamu dares to say he and Atsumu know them so well that they could navigate them dead.

Atsumu, who’s survived a shipwreck, swam back to land, and climbed these cliffs home while half-drowned, starving, and dehydrated, is about to die of fratricide because _he was never supposed to test this theory_.

“I’m fine!” Atsumu garbles around the lip of his sixth cup of tea. He’s swaddled in bandages and salves and he’s resting in the infirmary wing instead of his room because he’s not fine. The only reason Osamu hasn’t bound him to the cot is because Atsumu physically can’t stand on his own because his stupid twin _is not fine_.

Osamu says none of this. He doesn’t want this reunion spoiled by the storm raging in his chest. Atsumu at least looks better, eyes clearer and cheeks shiny with honey. Carefully packed bags of wet tea leaves are draped around his shoulders, dribbling little brown streams down his chest to stain the sheets pooled around his waist, and his skin’s already mellowing from the color of tsubaki to a healthier ruddy brown. The physician had disappeared to go threaten the cooks into making soup broth faster, so it’s just the two of them in the wing for now. It’s tense and awkward, Atsumu instinctively avoiding Osamu’s wrath and Osamu swallowing back the bitter words edging along his tongue. Instead, Osamu carefully catalogues the black and blue bruises scattered across Atsumu’s chest and trailing down past his sides, forced to stop at Atsumu’s hips where the soft white sheets are blocking his view but knowing the bruising trails all the way down, his rib cage tightening and aching with the rising count.

He realizes he’s glaring at the sheets so he forces his gaze back up, catching Atsumu chewing off the dead skin still clinging to his lips, beads of blood blooming under the blunt grind of his teeth. “Hey, stop that!”

Osamu reaches out to smack Atsumu automatically but freezes just as quick, hand hovering awkwardly between them. He drops it, then buries it in the folds of his robe, a hot flush rising up the back of his neck. Atsumu narrows his eyes to slits and he grumbles against the rim of his mug.

“I’m not made of _glass_.”

Osamu chews on the inside of his cheek, equally unhappy. He grabs the teapot and offers a refill as a silent apology, and Atsumu at least has the good grace not to reject it. The smell of bitter herbs fills the space between them as steam gently curls out of the cup, and the sullen line of Atsumu’s shoulders relax as he slowly sips his fresh tea.

It takes Osamu longer to unwind, hands clenched tight around his own long cold cup. He continues watches Atsumu through his fringe, taking in the way the setting gold sun softens his hollow cheeks and washes away the purple bags under his eyes until he almost looks back to normal. Atsumu doesn’t appear to mind, gaze unfocused as he stares at the rippling red-orange sea out past the window and mindlessly sips his tea.

Osamu clears his throat tentatively, pulling Atsumu back to him. “What happened to you, ‘Tsumu?”

To his shock, Atsumu’s whole demeanor blooms like a flower under the morning sun. He leans forward eagerly, eyes shining amber and lips pulled into a smile so wide they begin to bleed again.

Osamu’s hands flutter around him, useless, eyes wide at the sudden change. “‘Tsumu—“

Atsumu sighs, long and dreamy. “I was in the water and it was so dark and cold, but then _he_ came. He has the prettiest white wings you'd have ever seen and his eyes burn as bright as the sun and he's _beautiful_ , I thought I had died—“

“I— _What?_ ”

Atsumu doesn’t hear him, eyes glazed with memories ( _or hallucinations_ , Osamu thinks darkly) and too lost for Osamu’s words to find him. “—he carried me through the waves and gave me air and—“

“What are you—“

“—he's _incredible_ ,” Atsumu breathes, barely stopping for breath. “He's so strong, he barely had to stop and rest! He just swam and swam, keeping me warm when it was cold and rubbing water on my skin when it was hot—“

“ _Shut up!_ ”

Atsumu’s mouth snaps shut with an audible click. Osamu stares at him, chest heaving, eyes just as wide, and winces as Atsumu retreats into hunched shoulders and a shuttered expression. Osamu groans under his breath and falls forward, burying his face in his hands. He feels exhausted, like a puppet with its strings cut, and he takes a deep, shuddering breath before he drags his head back up.

“I’m sorry, I didn’t mean to yell.”

Atsumu snorts. He glares at his tea sullenly, finger dragging along the mug’s rim.

“I’m sorry for interrupting,” Osamu says again, this time rewarded with a brief glance. “I’m just...” Osamu chews over his words, then groans again and drags a hand through his hair. “It makes no sense.”

“What’s there to be confused about?” Atsumu grumbles obstinately. “I’m telling you exactly what happened.”

“You met a stranger in the middle of the ocean?!” Osamu laughs harshly, lips curling into a sneer before he can stop them. “You were half-drowned and dying of thirst, how was that not a hallucination of your mind trying to save yourself.”

“I don’t care if you don’t believe me, ‘Samu.” Atsumu scowls at him darkly. “I know what I saw.”

“I’m not saying you didn’t see it, I just don’t think it’s real!”

Atsumu flinches and Osamu curses his temper, pinching the bridge of his nose and forcing himself to take calming breaths.

 _He’s in a delicate state_ , Osamu reminds himself firmly. He breathes deeply through his nose and holds it tight, and his swelling anger resides just a bit. _Delicate state, delicate state_.

Atsumu knows though. He always knows. His scowl deepens and he slams back the rest of his tea. He slides into a sullen lump on his bed with his back to Osamu, uncaring of the still damp tea bags ruining the sheets, and pulls his covers up around his ears.

Osamu sighs wearily and drags his hand down his face. He reaches for Atsumu, but his hand freezes just millimeters away from his shoulder. His apology sticks in his throat, words suddenly thick like honey, and Osamu struggles to bridge the chasm.

The sheets twitch as Atsumu pulls them up higher. “Go _away_ , ‘Samu.”

Osamu grimaces and retreats. He tries to say goodbye, or at least some final reassurance, but again the words stick in his throat. He stands there for a minute, struggling to breath life to the relief that’s been fighting through his heart, but nothing comes. Osamu gives up and leaves the room, Atsumu’s sulking weighing on him like the air before a storm.

He allows his wallowing until he reaches his office and Kita’s reliably blank stare, and then he forces himself to shake off the worst of it. He has a ceremony to plan. Atsumu’s safe now, the rest can wait.

☼

It hadn’t been Atsumu’s idea to go out sailing.

The brothers love to go out on the water, live with a ship bucking beneath their feet and the wind pulling through their hair, especially this time of year when the schools of fish congregate in their waters and the tide swells gently along the hulls of their ships. But this year’s sailing season also held a coronation and wedding of nations and no time for frivolities. And no matter how Atsumu plays, he’s never shirked his duties.

No, it had been Osamu who pushes Atsumu up the gangplank with the instance that he's not needed, no point in dealing with a ceremony centered around someone else, all peppered with light barbs that he refuses to deal with Atsumu’s whining for missing his favorite pastime. His chest is hot and tight as he helps Atsumu pack his bags, and the feeling doesn’t abide until he watches Atsumu’s ship slip past the rocky outlooks and off to the horizon.

Then the news of blood dawns and a wrecking tempest reach their shore without Atsumu, and Osamu drowns standing on dry land.

☼

Frantic pounding pulls Osamu from his fitful dreams. The morning light is the weak gray of morning mists, mere hour’s change of light from the blue dawn Osamu had fallen asleep to.

“Sir!” the messenger cries from the other side of the door, “Your brother’s missing!”

The sluggishness snaps from his mind instantly and the next minute’s a blur as he runs from his room and yells for the full report. As he yanks on his boots, the messenger can only tell him that the main physician had come into work thirty minutes ago to find the prince's cot empty, and that the night nurse had been watching Atsumu until the blue morning hours. Osamu dismississes the messenger and with some quick mental math, he guesses how far Atsumu could’ve gone in his time window.

Scratching out the forest trails and more difficult hikes is easy enough to do, and Osamu picks up his twin’s trail quick enough. The clues are surprisingly well hidden for being created by a man drugged to the gills, but Osamu blazes past it, hot on his tail. He’s surprised the trail leads down to the shore given Atsumu’s recent ordeal, but the signs quickly yield the path to the brothers’ favorite cove. Osamu picks up his pace, less looking for signs of Atsumu’s passing and rather just picking up confirmation his hunch is right.

The twins’ cove is a small thing. It’s surrounded by tall shale cliffs that make most hikers second guess its stability and opens to the north to allow in the biting cold breeze. That alone wards off most lost visitors, making it perfect for the twins’ needs—it’s their secret, their place where no one else would follow. Most wouldn’t be able to see past the shallow, driftwood choked beach hugging the cliff’s base or cold steel blue waters swirling below to find the hidden nest of wonders it offers, but the brothers could spend lifetimes there exploring the rocky tide pools and underwater caves hiding beneath the unfriendly exterior.

There’s a small ridge that slips down the fifteen meter cliff—barely more than a foot’s width and dangerously steep—that ends on a thin, jutting outcrop that makes for a perfect diving platform or shallow shade. Osamu curses his fool of a twin as he carefully slides down the ridge, the rock slick with dew beneath his boots. This cove is particularly beautiful during sunrise, when the fog clings to the soft swells of the waves, slowly burning away as gold light spills over high cliff rises and color blooms across the rock and into the water. For all that wonder though, the twins are always careful about when they come. Rock and sea don’t care if a fool’s royalty or not.

“‘Tsumu’s head must be permanently sunbaked,” Osamu grumbles under his breath as he slides down the final meter. His foot slips just at the bottom and Osamu gasps as he smacks into the rough cliffside, shale slivers shaking loose to tumble into his hair and down his collar. “I’m going to kill him,” he mutters darkly yet again, shaking his head roughly as he reaches carefully for the sharp edge of the outcrop’s ridge.

But as Osamu climbs over that outcrop to enter their hidden world, the cove yields a new wonder to him—a creature of the sea with a man’s torso and the sinewy tail of a fish rising from the waves and looking around the shoal curiously.

Osamu gapes, eyes so wide they sting with the salty air. Then, he hears the unmistakable cry of an idiot. He whips his head around to see Atsumu wobble upright from his perch on the beach and clumsily wade into the water, eyes fixed on deadly temptation and waving it closer happily.

He launches himself into the water without thought, cold water soaking him through to the bone as he lands with a loud splash.

“ _ **Don’t you fucking dare!**_ ”

Osamu doesn’t recognize his own voice through his roar, but satisfaction rings through him as the mermaid startles and disappears beneath the waves in a flash of gold. Adrenaline still roars in his ears, heart pounding a tattoo against his chest as he runs to Atsumu, distressingly aware that the mermaid could appear as quick as it had disappeared. His beeline for Atsumu is frustratingly sluggish, the cove’s muddy sand sucking at his feet, and the sea spraying around him stings his eyes until his tears blind him. His mind screams at him to move faster, move _better_ —they’re clumsy, bumbling creatures in this environment compared to the mermaid lurking where Osamu can’t see. Even if they were standing together, there’s no way Atsumu could watch after himself, much less Osamu’s back.

Osamu’s heart rate doesn’t abate when he crashes into Atsumu, eyes only for the shore. “You fucking _**idiot,**_ what’re ya doing standing there we have to _go_ —”

Osamu’s not expecting Atsumu to resist just as furiously, shoving him back into the waves with an angry shout. “What the _hell_ ‘Samu, you scared him off!”

Osamu, with one arm tangled in seaweed and half his head underwater, stares back and wonders if his near-death has made his twin _fucking insane_. “Scared?! _Him?!_ ”

Atsumu throws his hands up in disgust and turns back to the waves, hands cupped around his mouth as he bellows, " _Shouyou!_ "

"Shouyou?!" Osamu demands.

"Shut up!" Atsumu snaps as he peers out across the water. The morning fog’s mostly burnt away, letting the early sunlight slip across the rippling tide in a blinding coat. No matter how Atsumu or Osamu squint against the harsh silver rays, they can’t see below.

Atsumu’s disappointed.

Osamu’s apocalyptic.

He kicks Atsumu’s legs out from under him and grabs his collar to shake him before Atsumu’s head slips underwater. “Are you stupid! Do ya want to die!”

Atsumu rolls his eyes and kicks Osamu in the ribs with surprising strength. It’s not near enough to make Osamu loosen his grip. “Shouyou wouldn’t let me die! He _saved_ me.”

“ _You named it?_ ” Atsumu’s next kick lands in the hallow just beneath his ribcage, ten times stronger, and Osamu releases him with a choked wheeze. The two don't bother to leave the water, uncaring of the stringy seaweed tangling around their ankles or the cold little waves lapping at their chests like playful kittens. Atsumu's too busy searching the shadows in the currents for his missing mermaid; Osamu stays because he won’t allow anyone else the pleasure of killing him. “Explain. Now.”

Atsumu blows a raspberry and Osamu’s face turns a delicate puce color. “You didn’t want to listen last night, why should I have to now?”

Osamu yanks Atsumu’s ear, relishing his yelp. “Now’s not the time for pettiness. _Explain_.”

Atsumu looks at Osamu and narrows his eyes, jaw set stubbornly. “ _No_ —”

“ _ **Atsumu**_.”

Atsumu grumbles and looks away sullenly. Osamu grits his teeth and tugs on Atsumu’s ear again, albeit less harshly this time.

“ _Alright_.” Atsumu squirms into an upright position, batting Osamu’s hand away. He takes a while to settle, pushing this way and back over the rocks strewed across the shoal’s floor, tugging his shirt irritably to pull it away from his sunburnt skin. The furrow between Osamu’s brow grows deeper as the sun creeps higher, burning away the mists lingering atop the water. He clenches his jaw tightly against the anger itching across his tongue, and waits.

“The storm took us by surprise,” Atsumu mumbles, knees pulled tight against his chest. “It was fast, it was madness, and no one could hear each other. By the time the sails ripped, most of the crew had already given up. Well, the crew that was remaining, a lot of them were swept over in the first hour.”

Atsumu looks at his hands and Osamu can vaguely make out the way they’re clenched together under the water. A muscle along Atsumu’s jaw twitches, and Osamu sees the shadows hiding underneath the reflections in Atsumu’s eyes. “I don’t know how, exactly, I went overboard. I think part of the main mast broke off, but it was dark, a wave had just crashed over me and Rintarou, and I was just trying to get to my feet. Then something was coming towards us, fast, and I’d barely managed to push Rintarou back down before it slammed into my chest. Next thing I knew, I was in the waves and couldn’t breathe.

“That’s when Shouyou came.” Atsumu looks up, eyes shining. “He pulled me above the waves. I passed out at some point during the night, but somehow he’d kept me alive. When I woke up the next morning, he’d made me a kelp net to help me float and was using his chest to keep my head above the water.”

Atsumu trails off, eyes dreamy, and Osamu’s lips twitch into a frown. Atsumu’s ship hadn’t been the newest, missing some of the most recent amenities, but it hadn’t been _old_. “How’d ya make it back here.”

Atsumu raises his eyebrow, unimpressed. “Shouyou, _duh_.”

“God, yer such a bag of dicks,” Osamu mutters under his breath with an eyeroll. Atsumu’s already looking livelier at the prospect of being punched.

Osamu really wonders about his twin sometimes.

“I meant, how the fuck did you make it back here so fast? You were in open waters, ya don’t seriously mean to tell me your mermaid swam you all—”

“Shouyou!” Atsumu shouts abruptly, bolting upright. He dives under the water and kicks off, leaving Osamu sputtering in his wake. Atsumu’s head pops up a few meters away, accompanied by the head of the mermaid from earlier, his twin oblivious to Osamu gaping after him.

The duo make no sign of moving, so Osamu reluctantly comes closer, eyes glued to the creature huddled within Atsumu’s arms. His hair is a brilliant orange, curly even out of the water and sparkling with water drops and woven charms of sea glass, and his tail gleams like the gold of the dying sun on the ocean’s horizon. He is very, very beautiful, and Osamu’s heart flutters tightly at the way Atsumu cradles him close despite the way his teeth gleam, deadly and sharp. The creature— _Shouyou_ —seems content to curl up against Atsumu’s chest and twine his tail around his leg, and Osamu feels like he’s falling despite the algae covered rocks biting into the backs of his thighs.

Shouyou stares back at him unblinkingly, eyes brighter than the scales shining on his tail. It’s unsettling how those gleaming big eyes settle on him, regardless of the way Shouyou’s cheek is pressed against the seam of Atsumu’s shoulder and his mouth is squished into a disturbingly adorable pout. Atsumu’s insistences from last night that he’d been saved by a man with the eyes of the sun suddenly seem much less incredulous.

Osamu narrows his eyes suspiciously, and the creature’s eyes widen before he twists to hide his face in the folds of Atsumu’s shirt with a quiet _meep_.

He’s _shy_ Osamu realizes with wonder as his world tips on its side for the second time that morning.

The need to make it up prickles underneath his skin, compounded by the way Atsumu scowls at him over Shouyou’s bright curls. Atsumu’s expression demands Osamu says something, and the guilty prickles turn to itching when Osamu finally realizes how nervous _Atsumu_ is about him meeting his savior.

Osamu scrunches up his nose before he can help himself. He’s never been one for words—not unless he’s insulting Atsumu—and he forces his expression to his blankest as he mulls over what to say.

“Hello,” he says softly, rewarded by large golden eyes peeking back up at him. Osamu licks the salt from his lips. “Thank you for saving my brother."

The creature doesn't move from the safe cradle of Atsumu's arms, but something crackling between the three seems to calm. Shouyou goes back to staring at Osamu with wide, unblinking eyes, and Osamu tries not to do anything that could appear threatening, no matter how his limbs ache with the need to _move_ or the way his ears ring with the echo of adrenaline.

The moment stretches, long and uncomfortable, before Shouyou hesitantly emerges from behind Atsumu's arm. He flashes a small, tight smile as he stares up through his wild bangs, and Osamu tries not to bare his teeth in his returning smile. "You're welcome." His accent is melodic, rounding out the sounds until they bump into each other, at odds with the faint rasp in his voice. Shouyou's eyes dart up to meet Atsumu's before they skip away back to the water. He smiles again, shyly, fingers tugging the seam of Atsumu's shirt nervously. "I couldn't let him drown."

Osamu’s expression remains carefully blank, but his gaze flicks between the mermaid and his twin. Atsumu looks so hopelessly enamoured as he stares down at Shouyou it makes Osamu _sick_.

"I'm glad," Osamu says, even as the acid taste still overwhelms his tongue. He gives Shouyou his most gentle smile, but his eyes stay trained on Atsumu. "Can you tell me how you brought him back? This idiot couldn’t tell a story to save his life.”

“ _Hey_ —” protests Atsumu, eyes flashing as he sticks his tongue out at Osamu. But Shouyou perks up, pulling away from his spot against Atsumu’s chest completely, and his lips pull into a wide smile. Both twins relax, even if Atsumu’s fists flex longingly on the water’s surface.

Unfortunately, Shouyou is a worse storyteller than Atsumu.

“—and so then the waves were like _WHOOSH_ and _PHWAH_ and they were _so big_ and I wasn’t supposed to leave Daichi’s side, but the false reef kept spitting out these bodies and then A’sumu was there and he was _gold_ and—“

“ _Breathe_ , Shouyou.” Atsumu’s face is pulled into a hopelessly besotted smile. Osamu wants to stuff seaweed in it to make him stop. But doing so would probably scare off Shouyou, so Osamu grits his teeth and tries to block out the expression mentally instead.

Shouyou stops and immediately breathes in deep, then looks so baffled Atsumu bursts out laughing. Shouyou opens his mouth and breathes again, a little furrow wrinkling his brow until a thought alights his face and he smacks his fist in his palm. “Right, you air-breathers have to do that. It’s so stupid, why did you lot bother making your talking hole your breathing hole too.”

The gills along Shouyou’s neck flutter indignantly as if to prove his point, and Osamu laughs unwillingly alongside Atsumu. Shouyou’s tail splashes against the water self-consciously, but his embarrassment quickly mellows after Atsumu hugs him, nose bumping sweetly along the edge of his hairline. Osamu’s laughter falls away.

The sun sits higher in the sky, gleaming off the water in gentle ripples and piercing through the steel-blue water to turn it clear. It’s a pleasant relief for Osamu’s sore eyes, finally giving him the chance to realize why the water drips away from Shouyou’s arms so oddly. He hadn’t been able to make them out when the water was bright white, but now they’re unmistakeable.

“You have wings,” Osamu murmurs with surprise.

Shouyou’s tail splashes happily and the edge of one flutters in the water. “I do!” He grins, impish, and eagerly thrusts out his arm. “Wanna see?”

He flexes his wrist before Osamu can reply, and the tip of his wing snaps out. Underwater, they had made Osamu think of the thin, delicate membranes of insect wings. Up close and out of the water, they’re more akin to large fins, running up along Shouyou’s side with thin, hard ridges ready to splay beyond Shouyou’s fingertips with a clever snap of the wrist. Osamu gathers the tip of the wing in his hands curiously, mouth fallen into a delighted _oh_ as he rubs the thick, sturdy skin between his fingers and admires how the light renders the wing near transparent.

Shouyou giggles, sounding like a bubbling brook, and his wing ripples in Osamu’s hand. “That tickles,” he murmurs, eyes sparkling beneath his fringe.

A cold breeze ripples across his neck and Osamu drops the wing immediately, Shouyou’s lips falling into a disappointed mue with it. Atsumu reaches out immediately, fingers curling in a bratty, universally recognized sign. “ _I_ wanna see Shouyou’s wings!”

Shouyou perks back up and extends his wings gleefully, soon dissolving into bell-peal laughter as Atsumu dances his fingers along the sensitive undersides of the fin’s ridges. Osamu watches from the side, chilled shivers crawling up his spine despite the sun beating down upon them.

☼

The brothers wave goodbye to Shouyou and watch him slip behind the waves before climbing back home, Osamu trailing behind Atsumu just in case. Atsumu’s infuriatingly perky on their way back, laughing as Osamu cracks his knuckles threateningly. Soon enough, they can see the castle’s gate over the sakura blooms.

Osamu stops dead, blood draining from his face. Atsumu skips ahead a few steps before he stutters to a halt and he frowns as he comes back to poke Osamu’s cheek obnoxiously. “‘Samu? You in there?”

“I was sent out because you disappeared.”

Atsumu raises his eyebrows and shrugs playfully. Osamu can tell he doesn’t get it, because the idiot still has a dreamy smile on his lips.

Osamu grabs his shoulders so he can’t escape, grip unyielding and tone as lifeless as a man at the gallows. “You disappeared, so I went to find you _before sunrise_ , and Kita-san and I are preparing for the _Itachiyama royal party_ to arrive in less than a week.”

Osamu can tell the moment it hits in the way Atsumu deflates under his grip and the color drains from his face so fast that even his sunburnt cheeks look pale. His eyes dart nervously to the now imposing ridge of the gate, and the twins finally pick up the faint panicked clamour from within the compound.

“Maybe if we wait a few hours, everyone will be so relieved when we return they’ll forget their anger?” Atsumu asks with a nervous lick to his lips.

Osamu laughs hallowly. “You honestly think that will help when we need to beg Kita-san’s forgiveness?”

Atsumu wilts further. “ _Fuck_. What’re we gonna do?”

Osamu ponders for a minute, before nodding his head decisively and gripping Atsumu’s bicep as hard as he can. “We meet our maker and hope he’s in a merciful mood.”

“‘Samu,” Atsumu wails, digging in his heels, “I’m too beautiful to die!”

Osamu eyes him critically over his shoulder. Atsumu does look much better, but his clothes drip pathetically as they bunch against his thin frame and not even the best burn salves could cure his peeling sunburn so fast. Osamu digs in his heels as well and pulls mercilessly. “Not right now you’re not.”

“ _‘Samu!_ ”

The debate becomes mute the minute they walk past the gate and the entire compound goes _dead_. Osamu tries to keep his shoulders from bunching around his ears at the ringing silence. The stares pass the twins completely, and he and Atsumu slowly turn around to see Kita sitting under the shade of Granny Suna’s food stall, calmly signing off festival permits and drinking tea.

Kita stares over his mug, as placid as ever. He signs another permit without taking his eyes off them, then pulls it from the stack with a harsh _snap_. “The next time you go off for playtime, you wait until after your responsibilities are completed.”

Osamu and Atsumu flinch together, heads bowed apologetically. “Yes Kita-san,” they say dutifully, uncaring of station.

Kita takes a long, slow sip. Atsumu squirms anxiously beside him, and Osamu elbows him discreetly. Then, mercifully, Kita turns away and waves them off. “Well, go on then.”

They scuttle past him and the silent crowds to the castle to clean up, tails firmly tucked between their legs.

After that, Osamu can’t seem to find the time to speak with Atsumu for the rest of the week. Kita keeps Osamu from escaping his paperwork by waking him up each morning himself and escorting him to his desk like a toddler, all with one perfectly shaped eyebrow raised and daring Osamu to make a fuss. Atsumu mostly just tries to stay out of the way of the frenzied wakes left by the event planners. He hadn’t been expected back until two days before the Itachiyama party arrival regardless, so he eagerly takes advantage of his lightened workload and disappears to the cliffs as soon as the sun rises, and staying away until the sun drips gold along the horizon. Osamu can barely catch his twin even when he is around, Atsumu avoiding Kita like a naughty child avoiding discipline and avoiding Osamu in the process.

That doesn’t mean he doesn’t catch Atsumu’s new hobby.

“Strange,” Kita remarks the morning before the Itachiyama party is scheduled to arrive. Osamu’s window is shut tight to block out the castle bustling itself into a fury, but the sweet earthy scent of chrysanthemums manages to seep through regardless with the rising heat. He wrinkles his nose and tries to pass it off as a pathetic sneeze.

“Oh?”

One of Kita’s many jobs is household inventory. Osamu’s offered to transfer it to someone like Aran, the actual head of the household, or even get Kita an assistant to handle the menial task, but Kita had just stared at him blankly before stating that the job is no problem and he doesn’t like interruptions to his routine. Unfortunately, it’s led to Osamu’s current predicament of having a million other things to do, but all of them ignored for an itemized list of everything Atsumu’s stolen from the house over the past week sitting on the desk before him.

Osamu doesn’t care that Atsumu’s taken to draping himself in sparkling jewelry and medallions, or that he’s been taking them out on his morning trips and returning with more and more pieces missing. He doesn’t care that Atsumu’s gotten so loose he’s started lifting from Mama’s souvenir teaspoon collection either, though he wishes Atsumu had at least had _some_ sense of moderation. Kita would have figured out the pattern in his snitching regardless, but he hadn’t had to make it so _easy_.

“Strange?” Osamu’s eyes go down Kita’s tidy list, finger tapping against his desk as he sees the obvious pattern in stolen trinkets he already knows is there.

Always small. Always shiny. Always _gold_.

Osamu’s expression doesn’t change, but his finger taps rapidly against his desk. He stares at the list despite already knowing it, despite having already tallied up everything over and over and weighed it against the other. Atsumu’s come back every time so far—he has to assume that’s how it’ll stay.

Osamu’s tone is light despite everything. “Don’t approve of ‘Tsumu’s new gold collecting hobby, Kita-san?”

“Not that.” Osamu looks up at that, surprised. Kita doesn’t turn away from his work—he could be reporting the weather for all he seems to care. “Strange that he doesn’t care about taking them out to sea. Shiny things attract dangerous things out there.”

“Oh?” Osamu asks again, trying to match Kita’s bland tone. He fails miserably, unable to sound like anything but small.

Kita looks up, head cocked to the side. It’s the most shocked expression Osamu’s ever seen on him. “Didn’t your parents’ tell you the stories?”

“No.”

Kita is the son of a fisherman and a merchant. His childhood was mostly spent on a boat, his teachers the waves and the winds and the ship’s rigging, his tutors the bustling fish markets and helping his mother do her books by candlelight. He grew up with more stories in him than a library and more superstitions than a paranoid old fool, and it was these things Kita had wrapped safe and secure in his heart after his parents’ had saved enough to send him away at sixteen for a formal education.

Osamu’s parents hadn’t been the storytelling type. Not unless it was about them and their accomplishments, and even those were left to the ever cycling tutors more often than not. The only stories Osamu remembers from his parents are from formal dinner parties where he and Atsumu had been stuffed into starched robes and told off for speaking unless spoken to.

Osamu leans forward to rest his chin on his hand, hiding the way his nails bite into his palm. “What were your parents’ stories about?”

Kita stares at him blandly, pen still poised over his paper. “A lot of the same thing, told in different ways. Man goes out to sea, either heartbroken or about to break. Man meets a creature most enchanting, beautiful enough to distract him from its teeth and a sweet voice that reminds him of home. Man falls for creature, and the sea runs red.”

Kita’s eyes return to his desk. “It’s all the same. Man falls in love with something he can’t hope to hold, then man dies.”

Kita says no more and goes back to his work, pen scratching diligently in his accounts book. Osamu tries to return to his, only for his eyes to be pulled to the gleaming sea outside his window, worry ringing in his ears.

☼

**Notes for the Chapter:**

> when i started this, i was thinking maybe i'd be able to bang out a little 3k au. maybe even 5k if i was feeling ambitious!
> 
> ...
> 
> this story covers 4 weeks. this is just the first one, and i got to skip most of it. the story doc is over 12k already and ive barely gotten started. in fact, im still writing as you read this. i haven't gotten a chance to beta anything for it, because i am still writing
> 
> help

**Author's Note:**

> [yell hi or rt on twitter if it strikes your fancy](https://twitter.com/adoranoodle/status/1228266303309303808?s=20)


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